Using a phased array wide angle two-dimensional echocardiograph we have demonstrated that it is feasible to noninvasively obtain paired biplane images of the left ventricle (LV) which are angiographic analogues and which approximate biplane angiograms in providing a geometrically independent measure of left ventricular volume. The method used to demonstrate this relationship involved tedious manual digitization of images for computer analysis, systematically underestimated volume but provided accurate ejection fraction. The goals of the project funded by NHLBI IR23 HL 22787-01 are: 1. To develop an improved method of measuring two-dimentional echograms of the left ventricle. 2. To apply this method to four two-dimensional echographic views of the left ventricle in a wide variety of patients and to determine which views or combinations of views and which algoithms are or is most reliable. 3. To improve the sensitivity of these techniques by employing provocative maneuvers such as hand-grip exercise in patients undergoing two-dimensional echocardiography. 4. To develop two-dimensional techniques for measuring the right ventricle, right atrium and left atrium. In the first year of funding we have validated a dedicated micro-processor light pen digitizing computational system and have used it to study 14 patients undergoing biplane echocardiography and cineangiography. Our results suggest that the most reliable echographic approach to obtaining LV volume is to employ orthogonal apical views (two and four chamber). This approach provides a measurement of volume which requires no correction and which is superior to the M-mode under all circumstances.